angdon could see Sophie was still shaken from recounting her experience of Hieros Gamos. For his part, Langdon was amazed to have heard it. Not only had Sophie witnessed the full-blown ritual, but her own grandfather had been the celebrant… the Grand Master of the Priory of Sion. It was heady company. Da Vinci, Botticelli, Isaac Newton, Victor Hugo, Jean Cocteau… Jacques Saunière.

"I don't know what else I can tell you," Langdon said softly.

Sophie's eyes were a deep green now, tearful. "He raised me like his own daughter."

Langdon now recognized the emotion that had been growing in her eyes as they spoke. It was remorse. Distant and deep. Sophie Neveu had shunned her grandfather and was now seeing him in an entirely different light.

Outside, the dawn was coming fast, its crimson aura gathering off the starboard. The earth was still black beneath them.

"Victuals, my dears?" Teabing rejoined them with a flourish, presenting several cans of Coke and a box of old crackers. He apologized profusely for the limited fare as he doled out the goods. "Our friend the monk isn't talking yet," he chimed, "but give him time." He bit into a cracker and eyed the poem. "So, my lovely, any headway?" He looked at Sophie. "What is your grandfather trying to tell us here? Where the devil is this headstone? This headstone praised by Templars."

Sophie shook her head and remained silent.

While Teabing again dug into the verse, Langdon popped a Coke and turned to the window, his thoughts awash with images of secret rituals and unbroken codes. A headstone praised by Templars is the key. He took a long sip from the can. A headstone praised by Templars. The cola was warm.

The dissolving veil of night seemed to evaporate quickly, and as Langdon watched the transformation, he saw a shimmering ocean stretch out beneath them. The English Channel. It wouldn't be long now.

Langdon willed the light of day to bring with it a second kind of illumination, but the lighter it became outside, the further he felt from the truth. He heard the rhythms of iambic pentameter and chanting, Hieros Gamos and sacred rites, resonating with the rumble of the jet.

A headstone praised by Templars.

The plane was over land again when a flash of enlightenment struck him. Langdon set down his empty can of Coke hard. "You won't believe this," he said, turning to the others. "The Templar headstone—I figured it out."

Teabing's eyes turned to saucers. "You know where the headstone is?"

Langdon smiled. "Not where it is. What it is."

Sophie leaned in to hear.

"I think the headstone references a literal stone head," Langdon explained, savoring the familiar excitement of academic breakthrough. "Not a grave marker."

"A stone head?" Teabing demanded.

Sophie looked equally confused.

"Leigh," Langdon said, turning, "during the Inquisition, the Church accused the Knights Templar of all kinds of heresies, right?"

"Correct. They fabricated all kinds of charges. Sodomy, urination on the cross, devil worship, quite a list."

"And on that list was the worship of false idols, right? Specifically, the Church accused the Templars of secretly performing rituals in which they prayed to a carved stone head… the pagan god—"

"Baphomet!" Teabing blurted. "My heavens, Robert, you're right! A headstone praised by Templars!"

Langdon quickly explained to Sophie that Baphomet was a pagan fertility god associated with the creative force of reproduction. Baphomet's head was represented as that of a ram or goat, a common symbol of procreation and fecundity. The Templars honored Baphomet by encircling a stone replica of his head and chanting prayers.

"Baphomet," Teabing tittered. "The ceremony honored the creative magic of sexual union, but Pope Clement convinced everyone that Baphomet's head was in fact that of the devil. The Pope used the head of Baphomet as the linchpin in his case against the Templars."

Langdon concurred. The modern belief in a horned devil known as Satan could be traced back to Baphomet and the Church's attempts to recast the horned fertility god as a symbol of evil. The Church had obviously succeeded, although not entirely. Traditional American Thanksgiving tables still bore pagan, horned fertility symbols. The cornucopia or "horn of plenty" was a tribute to Baphomet's fertility and dated back to Zeus being suckled by a goat whose horn broke off and magically filled with fruit. Baphomet also appeared in group photographs when some joker raised two fingers behind a friend's head in the V-symbol of horns; certainly few of the pranksters realized their mocking gesture was in fact advertising their victim's robust sperm count.

"Yes, yes," Teabing was saying excitedly. "Baphomet must be what the poem is referring to. A headstone praised by Templars."

"Okay," Sophie said, "but if Baphomet is the headstone praised by Templars, then we have a new dilemma." She pointed to the dials on the cryptex. "Baphomet has eight letters. We only have room for five."

Teabing grinned broadly. "My dear, this is where the Atbash Cipher comes into play"